Ques: Is a C# class without constructor possible?

Yes, C# class without constructor is possible. 

We can have a class without any constructor in C#. If we don’t declare any constructors in a class, the compiler automatically provides a public parameterless constructor. And it is ok to instantiate the class without a constructor.

In the below C# code example program, we don’t have any constructor in the class Person.

class Person
{  
    //This class has no constructor
    public void getPersonProfile()
    {
        Console.WriteLine("Base class:getPersonProfile() have no constructor");
    }
}

class Program
{
    static void Main(string[] args)
    {
        //Create object of person
        Person person = new Person();
        person.getPersonProfile();
    }
}